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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
What is the resistance of an object if a voltage the voltage of 40 V produces a current of 5?
Ohm's Law: Resistance = Voltage divided by Current
40 volts divided by 5 amperes = 8 ohms.
What do you mean by wattless current and power factor in AC?
Watts = Current x Voltage x Power Factor In an AC circuit both the voltage and current are sine waves. When they are in phase (waveforms lie over top of one another) the PF is one. As they become out of phase the PF decreases to zero. This happens when the phase difference is 180 degrees. In this case the positive peak of current is at the same place in time as the negative peak of voltage or vice versa. So when PF is zero you coul say you are getting zero watts.
AnswerAn a.c. load current can be resolved into two components. One, in phase with the supply voltage, and responsible for supplying true power to the load. The other, at right angles to the supply voltage, and responsible for supplying reactive power (e.g. the magnetic field, in the case of a motor). As reactive power is sometimes termed 'wattless power', we can say that the second component of this current is 'wattless current'.
What is a triangle wave voltage function?
Triangle-wave voltage signal is a periodic signal that always has a constant positive and negative slope and no zero slope. It is exactly how it is sounds... a triangle shaped wave.
/\/\/\/\/\/\/\/\/\/ - just like that.
Nothing in this world can naturally produce perfect triangle waves. Every vibrates as periodic sinusoid. Triangle waves can be generated from sin waves with the use of Fourier Series.
http://en.wikipedia.org/wiki/Fourier_series
By summing sin waves with different periods nearly any time-continuous signal can be created.
-VM
How do you load the monarch 1115?
ftp://www.servisource1.com/user_documentation/1115/tc1115oibr-revba.pdf
Why electric current across a wire drops?
Electric current does not drop. Electric voltage, however, drops across a wire because the wire has non-zero resistance. (Do not confuse electric current with electric voltage - they are not the same.)
The reason current does not drop is that, in a series circuit, according to Kirchoff's current law, the current at every point in a series circuit is the same.
In direct current the charge carries always flow in the same direction, while in alternating current they change direction repeatedly, meaning overall there is no net direction.
What happens to the damping when the settling time increases in a derivative error compensation?
increase
How many amps is a 380 volt 0.18 kw 3 phase electric motor?
The formula you are looking for is Amps = kW x 1000/1.73 x E x pf.
Use .84 for a power factor value.
Can you read 120 volts line to neutral even with a severed neutral?
It depends on what side of the break that you are reading from. On the neutral load side of the break there will be no reading. On the panel neutral side of the break you will get a reading.
What is the effect on rotor speed during fault?
During a fault, the rotor speed of a synchronous machine typically decreases due to the sudden loss of mechanical power input or an increase in electrical load. This drop in speed can lead to a reduction in the machine's ability to maintain synchronous operation, potentially causing it to fall out of synchronism with the grid. In contrast, for induction machines, the rotor speed may increase momentarily due to the change in slip, but it will ultimately decrease as the machine responds to the fault conditions. Overall, the rotor speed is affected by the nature and severity of the fault, impacting system stability and performance.
Why is a capacitor used in a starter?
A capacitor is used to reduce the arcing when the ignition circuit's contacts open and close.
A longer answer
To be answered fully, this question needs to give more information:
Is the question asking about a starter for an aero engine or a ship's engine, or for the engine on a car, truck or other vehicle?
Or is the question asking about the starter for a fluorescent light fitting?
Answer for a fluorescent light fixture's starter
A capacitor is a device which absorbs and stores energy in the form of an electric field.
When we switch on the light, the fluorescent tube initially requires more energy than is required for when it is continually running.
This is because the tube's two filaments - one at each end of the tube - have to be supplied with current to give them enough energy to heat up and glow. Their extra heat makes an arc flash across the tube, between the two filaments.
The arc will then continue running across the tube once the filaments have been disconnected from the power source. *** (See Note below.)
After the arc has started across the tube, a switch inside the starter must open to break the supply of current to the filaments.
Without a capacitor, a secondary arc would start across the open contacts of the switch inside the starter and that arc would quickly cause those contacts to burn away. The capacitor absorbs the energy which would otherwise start that secondary arc to glow. That is why a capacitor has to be used in the starter for a fluorescent lamp.
*** Note
As part of the lighting fixture there has to be a special inductance coil - called a "choke" - that is wired in series with the fluorescent tube.
The choke's purpose is to limit the amount of current drawn by the arc whilst the tube is lit up. Without the choke the arc would act like a short circuit and would cause the circuit breaker or fuse protecting the lighting circuit to trip or blow in order to cut off the supply of current.
What are the different types of filament winding process?
generally three types....one is lathe type,& another 2 are racetrack and tumble type winders
What is the KWm value for 801 KVA?
kWe = (kWm -Fp) x ha or kWe = kWm x 0.90 x 0.95 (<10L engine)
kWe = (kWm -Fp) x ha or kWe = kWm x 0.95 x 0.95(>10L engine)
kWe = kVa x 0.8
What is the symbol for three phase power?
There is not any symbol for 3 Phase Powe, but it can be represented by 3O, 3Ph.
What is SAP with respect to SCADA systems?
HI guys
I have a question:what is SAP with respect to SCADA system?
Why a coiled wire does not short the circuit?
I suspect that it is because a coiled wire becomes an electro-magnet which disipates and uses energy, and is therefore not recognized as a short.
Insulators what sizes for what voltages?
Size matters little in identifying a good insulator, unless you mean material thickness. The breakdown strength of the insulating material affects how thick the material has to be in order to sustain a specific voltage difference without harm done to any one or thing. The breakdown strength is normally expressed as volts per unit length (aka thickness). I presume you can get the information from a science or engineering handbook or manufacturing datasheet. You need to over-design and allow extra thickness than what the paper says.
How do you calculate Mean Generation Time?
g=(log Nt- log Nto)/log 2 where N=absorbance reading @ time indicated
MGT= (t-to)/g
the number u are seeking is 0.639
Mike Farady actually did help invent the first electical generator
Depending on the distro... you need to limit the output per phase. You can use 2 16amp and 1 32 amp per phase.
Yes, IF the generator has overcurrent protection and each circuit on your distro is individually protected as well (most are). You will not be able to load the distro to it's full capacity of 125 amps (obviously), you will be limited by the genny's rated output.
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
